1. Field of the Present Invention
The present invention relates to a lighting apparatus having an electrical insulation structure of a dimmer and a driver, the apparatus including: an input power supply unit; a converter for converting input power into lighting unit supply power; a lighting unit applied with the lighting unit supply power to emit light; a dimmer for inputting a dimming signal for controlling the lighting unit; a PWM generation unit for receiving the dimming signal and generating a PWM signal; and a PWM control unit for controlling the lighting unit supply power according to the PWM signal, in which the input power supply unit, the converter, the lighting unit and the PWM control unit are connected to a first ground, the dimmer and the PWM generation unit are connected to a second ground, and the first ground is electrically separated from the second ground.
2. Description of Related Art
A light emitting diode (LED) is a kind of semiconductor device for converting electrical energy into light. The LED has advantages of low power consumption, semi-permanent lifespan, fast response time, safety and eco-friendliness compared with existing light sources such as a fluorescent lamp, an incandescent lamp and the like. Particularly, an LED lighting apparatus may carry out various performances by controlling the order of turning on and off LEDS installed in a plurality of arrays, colors and brightness of emitted light, and the like.
Therefore, a lot of studies are under progress to substitute LEDs for a conventional light source, and use of the LEDs as a light source of various lighting apparatuses used indoor or outdoor, such as lamps, LCD devices, electronic signboards, street lamps and the like, is on the rise. Particularly, the LEDS are used for general lighting of indoor interiors, stage lighting for making a specific atmosphere, advertisement lighting, landscape lighting and the like.
A lighting apparatus may be installed on an outer wall of a building, in a park, on the street as a street lamp, on a bridge rail, in a theater and the like as a landscape lighting apparatus, and the size and applied system may vary according to applied purposes, targets or positions. That is, a lighting apparatus for an outer wall of a building is used to be simply displayed on the outer wall of a building in the shape of a stripe just for blinking in an single or combined color, and lighting apparatuses installed in a park, on a street, on a bridge rail or the like are irregularly installed according to the shape of a target object to blink or change colors.
In addition, LED lighting is rapidly distributed owing to a long lifespan and high efficiency compared with conventional lighting, and dimmers capable of changing illuminance according to change of climate and time are commercialized. Control methods of the dimmers can be divided into wireless and wired communication methods, and particularly, when a wireless communication method is used, brightness is adjusted by handling a Dim(+−) line in each driver.
In addition, dimming control of a lighting apparatus diversely used in a variety of fields recently should be performed quite precisely. This is more than simply turning on and off a lighting apparatus, and it is required to precisely control the lighting apparatus at a variety of illuminance levels such as low, low-medium, medium, medium-high, high and the like according to the requirement of a user.
Meanwhile, a dimmer and an LED driver should be electrically connected for wired dimming control of a lighting apparatus. In the case of a conventional lighting apparatus, there exists a potential danger of a defect since the ground of the dimmer is electrically connected (equal potential) to an LED lighting unit due to the electrical connection.
At this point, a condition of connecting one dimmer to several LED drivers and LED lighting units exists as a general field implementation condition, and there may be a state in which a plurality of unintentionally connected LED lighting units has the same common potential. Accordingly, if a separate interface for handling the dimmer does not exist, there may be a problem of flowing leakage current of the LED lighting units through a human body when a user handles the dimmer.